Safety-valve fob



H. WATERMAN.

SAFETY VALVE.

Patented N0v.15,1853.

a m i UNITED STATES PATENT OFFICE.

HENRY WATERMAN, OF HUDSON, NEW YORK.

SAFETY-VALVE FOR LOCOMOTIVE-ENGINES.

Specification forming part of Letters Patent No. 10,243, dated November15, 1853; Reissued July 9, 1867, No. 2,675.

To all whom it may concern:

Be it known that I, HENRY WATERMAN, of the city of Hudson, county ofColumbia, State of New York, have invented a new and Improved Mode ofConstructing the Safety- Valves of Locomotive-Engines; and I do herebydeclare that the following is a full and exact description thereof,reference being had to the accompanying drawings and letters ofreference marked thereon.

Owing to the-jolt-ing of the locomotive engine'when in motion it wasfound necessary at an early day to discard the use of the simple weightupon the lever of the safety valves as large portions of steam would beblown 0E when the pressure was below the point indicated by the meanpressure of the weight upon the valve, as for instance when the boilerwas suddenly thrown upward the weight would continue to go up, so thatby the recoil and momentum the valve would be a portion of the timeraised from its seat and the steam allowed to blow off when below thedesired point of pressure, the spring balance was substituted and hasbeen generally used or applied to the lever of safety valves.

It has been long known that the soring balance is an imperfectindication o the pressure of steam from the following causes. The safetyvalve in rising will raise the outer end of lever that rests upon,though a much greater distance than the valve itself as the proportionsof power of the lever, as for instance a lever of a power of twelvetimes, resting on a valve say ,two inches diameter, when the valve israised to its full capacity say one half inch will raise its outer endsix inches a distance quite impossible with an ordinary spring balancewithout greatly increasing the pressure balance consequently at the sametime increasing the pressure of the steam, so that it will be seen anadequate discharge cannot take place with a spring balance resting upon,taking another instance, suppose a valve to raise one eighth of an inch,which allows an escape of about one fourth the capacity of the valve,the outer end of lever will rise one and a half inch, if to this aspring balance is attached with a scale of one twentieth of an inch tothe lb. it is evident that the pressure will be increased thereby thirtylbs. per inch. To remedy this difliculty I propose to use the simpleweight and lever so as to attain as near as possible a constant anduniform pressure upon the valve and in order to prevent the vibrationsof the Weight and lever I apply to outer end of lever a rod thatdescends vertical by which the weight is suspended to lever, at thebottom of said rod below the weight attach a small piston of about threeinches diameter surrounding this piston I place a cylinder in which thispiston is allowed to move freely and easily, the cylinder is firmlyattached to boiler or other convenient parts, into this cylinder I put afluid, mercury, oil, alcohol, or water, I prefer good sperm oil, thisfluid must fill the cylinder to near the top so as to completely coverthe piston, it is evident that the piston can move no faster than thefluid is made to pass by the piston and that it will check all suddenvibrations yet freely pass to a position due to pressure &c. By havingan ade quate facility of discharging surplus steam we have succeeded insecuring an uniform temperature and pressure in the locomotive boiler,preventing almost entirely the difliculty of leakage of tubes, rivetedjoints so commonly caused by these variations, also design is as a surepreventive of explosion from these causes.

A, represents the rear part of boiler.

B, represents the ordinary safety valve.

C, represents the ordinary lever.

D, represents the weight.

E, represents the rod upon which the weight is suspended to lever.

F, represents the piston attached to rod E.

G, represents the cylinder in which the piston F is allowed to movefreely.

H, is stand by means of which the cylinder is attached to boiler A.

I I I I represents the fluid in cylinder G which covers the piston F.

That I claim as my improvement and desire to secure by Letters Patent isi The piston F attached to the weighted end of the valve lever withinthe cylinder G and immersed in the liquid in the cylinder, combined andoperating in the manner and for the purposes herein discribed.

HENRY WATERMAN.

Witnesses:

DARIUS PEoK, JAMES CLARK.

[FIRST PRINTED 1913.]

